/**
 * Copyright 2009-2020 the original author or authors.
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.ibatis.type;

import java.io.Reader;
import java.sql.*;

/**
 * The {@link TypeHandler} for {@link Clob}/{@link Reader} using method supported at JDBC 4.0.
 * @since 3.4.0
 * @author Kazuki Shimizu
 */
public class ClobReaderTypeHandler extends BaseTypeHandler<Reader> {

	/**
	 * Set a {@link Reader} into {@link PreparedStatement}.
	 * @see PreparedStatement#setClob(int, Reader)
	 */
	@Override
	public void setNonNullParameter(PreparedStatement ps, int i, Reader parameter, JdbcType jdbcType)
			throws SQLException {
		ps.setClob(i, parameter);
	}

	/**
	 * Get a {@link Reader} that corresponds to a specified column name from {@link ResultSet}.
	 * @see ResultSet#getClob(String)
	 */
	@Override
	public Reader getNullableResult(ResultSet rs, String columnName)
			throws SQLException {
		return toReader(rs.getClob(columnName));
	}

	/**
	 * Get a {@link Reader} that corresponds to a specified column index from {@link ResultSet}.
	 * @see ResultSet#getClob(int)
	 */
	@Override
	public Reader getNullableResult(ResultSet rs, int columnIndex)
			throws SQLException {
		return toReader(rs.getClob(columnIndex));
	}

	/**
	 * Get a {@link Reader} that corresponds to a specified column index from {@link CallableStatement}.
	 * @see CallableStatement#getClob(int)
	 */
	@Override
	public Reader getNullableResult(CallableStatement cs, int columnIndex)
			throws SQLException {
		return toReader(cs.getClob(columnIndex));
	}

	private Reader toReader(Clob clob) throws SQLException {
		if (clob == null) {
			return null;
		} else {
			return clob.getCharacterStream();
		}
	}

}
